Aims Herbaceous species can have compensatory growth after grazing. Clonal integration contributes greatly to the re-growth of clonal plants. To date, however, very few studies have addressed how clonal integration affects bamboos’ regeneration at a ramet level. Our objectives were to test the following hypotheses: (1) clonal integration benefits bamboo’s compensatory growth greatly after grazing and (2) differences in branching pattern of rhizomes lead to different contributions of clonal integration to the compensatory effects.
Methods In Tangjiahe National Nature Reserve, we subjected Fargesia scabrida and F. denudata ramets within 1.2 m × 1.2 m plots to four clipping treatments, i.e., no clipping and 25%, 50% and 75% shoot removal, and kept rhizomes at the plot edges either connected or disconnected.
Important findings In plots with no clipping, rhizome severing stimulated new shoot generation and population recruitment of F. scabrida, but reduced the height and biomass of new shoots. The shooting rate and recruitment of F. denudata were significantly decreased in plots where rhizomes remained connected. When rhizomes were kept connected, 25% clipping reduced the biomass of F. scabrida, and 25% and 50% clipping reduced recruitment of F. denudata. However, rhizome severing increased the recruitment of F. denudata. Under 75% clipping, the recruitments of both bamboos did not decrease significantly, but the quality of new shoots declined. Such negative effects were negated or greatly ameliorated in F. scabrida when rhizomes were connected. In general, clonal integration contributes greatly to the growth of new ramets, but contributes little to compensatory growth of both bamboos after grazing.

Aims The growth relationship between twig and leaf is a strategy that plant canopy structure employs to space resources and enhance photosynthetic efficiency and competitiveness through configuration adjustments. Our objective was to examine how Stellara chamaejasme exploited twig and leaf configuration to explore the effects of slope change.
Methods In the upper reaches of Shiyang river, Gansu Province, China, 80 plots were set up at intervals of 20 m from the foot of a mountain along eight aspects. GPS was used to record latitude, longitude and altitude of each plot. Community traits were investigated and five S. chamaejasme were cut randomly on each plot for measurement of twig length, twig number, leaf area and leaf number. ArcGIS was used to set up digital elevation model (DEM) and abstract slope data of the study site. The 80 plots were divided into 0°-10°, 10°-20° and 20°-30° slope gradients. Values for twig and leaf traits were logarithmically converted, and then the standardized major axis (SMA) estimation method was used to examine the allometric relationship between twig number, twig length, leaf number and leaf length.
Important findings Twig length, twig number and leaf area of S. chamaejasme gradually decreased along the slope gradient. Significant allometric relationships between leaf number and twig length and between twig number and twig length were found to be consistent in all three slope gradients. Growing speed of twig length was greater than the speed of leaf number, and the growing speed of twig number was greater than the speed of twig length. However, there were significant differences in SMA slope in the three slope gradients, suggesting that slope constrains the leaf number and twig number that can be supported by a given twig length.

Aims Ecosystem carbon uptake or release is influenced by land uses. However, few quantitative studies have been made to give accurate explanations. Based on field measurements of gas exchange and water relations at the leaf scale and the ecosystem scale in temperate grasslands locating in northern China, we aim to 1) clarify the difference in carbon exchange between the leaf scale and the ecosystem scale in different land uses; 2) understand how human activities influence the carbon pools at the ecosystem scale by analyzing changes in gross primary productivity (GPP) and ecosystem respiration (R_eco); and 3) explore whether water condition in semi-arid steppe restricts CO₂ absorption at the ecosystem level.
Methods We selected three dominant spcies, Stipa grandis, Artemisia frigida and Leymus chinensis, based on quadrat surveys. Some ecophysiological indexes were measured using a modified LI-6400 in the sample plots of three land use patterns: enclosed plots, mowed plots and grazed plots. We calculated net ecosystem CO₂ exchange (NEE), GPP, R_eco and water use efficiency (WUE) with the measured results. All data were analyzed using one-way ANOVA and t-test of SPSS.
Important findings By comparing the carbon exchange of dominant species at the ecosystem scale, we found that carbon exchange varies with change of land use. NEE and GPP of the ecosystem in the grazed plots are different from those in the enclosed plots and the mowed plots, and GPP is more dependent on R_eco. In grazed plots, the diurnal change of NEE shows C uptake, but in the other two plot types it appears to release C. The phenomenon that negative net photosynthetic rate (P_n) returns to positive values from midday to dusk should be a special reaction of plants living in grasslands to protect themselves under high light and temperature conditions. There is no difference in WUE at the ecosystem scale, but the tendency of evapotranspiration (ET) is not the same; nevertheless, the degree of fluctuation of WUE for the same species at the leaf scale is largest in the grazed plots and smallest in the enclosed plots.

Aims Vegetation restoration is always a key problem and primary objective in restoration ecology. Our objectives were to evaluate forest restoration and reconstruction in Mengshan Mountain, including the impact on plant diversity of using different tree species in afforestation, and to select species for afforestation, in order to provide the basis for regulation and prediction of forest vegetation restoration and reconstruction in the Yimeng Mountain Area.
Methods Six kinds of major artificial forest over 40 years in age were selected for study using a typical sampling method. Species richness, Shannon-Wiener diversity index, Simpson diversity index and Pielou evenness index were used to evaluate species diversity of the tree, shrub and herb layers. Analysis of tree diameter-class distribution was applied in determining the type of development of the plant.
Important findings Each of the four indexes indicated that Pinus densiflora, Quercus variabilis, P. thunbergii, Larix kaempferi and Robinia pseudoacacia have better outcomes in afforestation and P. tabuliformis has relatively poor outcomes. In the tree layer, the four diversity indices of the P. tabuliformis artificial forest community were significantly different from those of P. densiflora, Q. variabilis, P. thunbergii, L. kaempferi and R. pseudoacacia artificial forest (p < 0.05). In terms of diversity, shrub layer > tree layer > herb layer, and the differences were significant (p < 0.01). There are 29 expansive species, 3 seclusive species, 9 enhancing invasive species and 11 randomly invasive species. Pinus densiflora and P. tabuliformis had great difficulty in population regeneration, and L. kaempferi had no seedlings. Shrub layers and herb layers may be the key factors hindering the natural regeneration of coniferous forest. Fifteen kinds of species for afforestation of Mengshan Mountain have been screened, including seven species for early afforestation (A) and eight for afforestation (B). Two types of A1 (constructive species) are P. densiflora and P. tabuliformis. Five types of A2 (companion species) are Dalbergia hupeana, Fraxinus rhynchophylla, Cerasus serrulata, Albizia kalkora and Carpinus turczaninowii. Two types of B1 (constructive species) are Q. variabilis and Q. acutissima. Six types of B2 (companion species) are Sorbus alnifolia, Q. dentata, Diospyros lotus, Celtis bungeana, Celtis koraiensis and Lindera obtusiloba.

Aims The encroachment of Phyllostachys pubescens into woodland was commonly thought to lead to a change in the amount of nutrient stored in the ecosystems. Our objective was to investigate the soil nutrients of soil organic carbon (SOC), total nitrogen (STN) and total phosphorous (STP) heterogeneity at two sides of the bamboo and broad-leaved forest interface (BBLFI), i.e., P. pubescens forest (PPF) - evergreen broad-leaved forest (EBF) transition, and to quantify the contribution of fine roots to the accumulative difference in soil nutrients.
Methods We selected typical BBLFI plots straddling PPF and EBF in natural areas around the Dagangshan Forest Ecosystem Research Station, State Forestry Administration. We investigated the distribution and dynamics of soil nutrients, fine root biomass, annual production and decomposition rate in 2010-2011 by means of sequential coring and ingrowth into cores. We calculated the fine roots C, N and P stocks, SOC, STN and STP pools and the contribution of fine roots to soil nutrient heterogeneity at two sides of BBLFI.
Important findings There was a significant soil nutrient difference between the two sides of BBLFI. The SOC and STN contents in PPF were 20.51 and 0.53 g·kg^-1, respectively, which were higher than in EBF by 34.53% and 50.35%, respectively, but the STP was 25.54% lower. Fine root biomass, nutrient stock and amount of return to soil between two sides of BBLFI were also obviously different. PPF root biomass was 1201.60 g·m^-2, which is 5.86 times as much as EBF. Nutrient stock was 591.42 g C·m^-2, 5.44 g N·m^-2 and 0.25 g P·m^-2, which were 6.12, 3.77 and 3.11 times higher than EBF. The amount of return nutrient was 278.54 g C·m^-2·a^-1, 2.36 g N·m^-2·a^-1 and 0.11 g P·m^-2·a^-1, which were 6.93, 4.29 and 3.67 times higher than EBF, respectively. The fine roots of the two sides decomposed at almost the same rate. The annual contribution of fine roots to the soil nutrient heterogeneity was 76.79% for SOC and 28.33% for STN, but P returned from dead fine root slowed the progression of forming STP heterogeneity by 6.17% annually. These findings indicated that bamboo encroachment had changed the EBF soil nutrients, leading to a significant accumulative soil nutrient heterogeneity at two sides of BBLFI, and fine roots played an important role in forming this heterogeneity for SOC and STN.

Aims Our objective was to investigate the effect of plant growth pattern (single or mixed) of two emergent plants (i.e., Phragmites australis and Typha orientalis) on the microbial biomass and community structure of the rhizosphere in two adjacent shallow lakes in Tianjin, China.
Methods The microbial biomass and community structure were assayed by using phospholipid fatty acid (PLFA) and polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) techniques. Cluster analysis of the microbial PLFA profiles was performed using hierarchical clustering according to the between-groups linkage method using the software package SPSS 13.0 for Windows.
Important findings The PLFA results showed that microbial biomass in the plant rhizosphere was higher than those in the non-rhizosphere, except for the P. australis rhizosphere in Aiwan Lake. The microbial biomass was significantly higher in the T. orientalis rhizosphere sediments than that in the P. australis rhizosphere sediments in both lakes. The microbial biomass of the same plant’s rhizosphere was influenced by pattern of plant growth (single or mixed). As the growth condition (plant height) was similar in the two lakes, there was only minor difference in the microbial biomass of the T. orientalis rhizosphere. When the two plants grew together, the growth of P. australis was significantly inhibited, and significantly lower microbial biomass was assayed than that under the separated growing condition. The gram-positive bacteria (G⁺) were less than that of the gram-negative bacteria (G^-) in all samples. Moreover, the ratio of G⁺ to G^-in the plant rhizosphere was less than in the non-rhizosphere. Microbial community structure was found to be related to the plant species. Little difference in microbial community structure was observed in same plant rhizosphere sediments between the two lakes; however, apparent differences in the bacterial community were detected between the two different plant species.

Aims Spacing interval is a cultivation technique to obtain high yield. Our objective was to investigate the effects of spacing interval on canopy characteristics and yield in winter wheat (Triticum aestivum) under different planting patterns of wide bed planting methods with 8 cm drilling width and conventional drilling planting methods with 2 cm drilling width.
Methods A field experiment was conducted in growing seasons of 2010-2011 and 2011-2012, growing multi-spike winter wheat cultivar ‘Aikang 58’ under different planting methods with three spacing intervals of 7, 12 and 17 cm for wide bed planting methods and 20 cm of row spacing for conventional drilling planting methods. Time-course measurements were taken on canopy leaf area index, mean leaf angle, canopy openness, light interception, canopy temperature, relative humidity and yield during the experimental periods.
Important findings Compared with conventional drilling planting methods, the leaf area index, mean leaf angle, light interception, relative humidity, spikes numbers, biomass and grain yield for wide bed planting methods are higher, while canopy openness and temperature are lower. Subsequently, spike numbers per unit area increased by 4.8%-16.4% (in 2010-2011) and 8.9%-21.0% (in 2011-2012) and yield increased by 2.96%-15.94% (in 2010-2011) and 4.09%-14.23% (in 2011-2012). Leaf area index, mean leaf angle, light interception, relative humidity and spike numbers decreased, and canopy openness and temperature increased with increased spacing interval under wide bed planting methods. Grain number per spike, grain weight, grain yield, biomass and harvest index are the highest in the 12 cm treatment and lowest in the 7 cm treatment. It can be concluded that 12 cm spacing interval under wide bed planting methods can be used as a feasible, promising planting pattern with reasonable canopy architecture and sufficient light distribution and interception and favorable microclimate.

Aims There are great differences in yield and quality of different quality types of peanut (Arachis hypogaea), and there is a significant negative correlation between different quality traits in one cultivar. We conducted an experiment to study the differences of quality formation and cell ultrastructure in different quality types of peanut.
Methods A high-protein variety, ‘XB023’, and a high-fat variety, ‘Luhua 9’, were planted in an agricultural experiment station field with a randomized block design in the 2010-2011 growing season. We observed the protein, fat and soluble sugar content of seeds while the pegs grew into the soil for 10-60 days, the components of amino acids and fatty acids and the changes of ultrastructure in cotyledon cells during different development phases.
Important findings The protein content of ‘XB023’ was lower than that of ‘Luhua9’ in the earlier stage of seed development, but significantly higher in the late development phase. The essential amino acid contents of ‘XB023’ were higher than those of ‘Luhua 9’, with glutamate, lysine and leucine contents being significantly different. Accumulation of fat in ‘XB023’ was lower than that of ‘Luhua 9’ throughout the development phases, and fat content of ‘XB023’ decreased in the late stage. The content of soluble sugar and the oleic/linoleic (O/L) ratio of ‘XB023’ were significantly lower than in ‘Luhua 9’. Starch grains, lipid bodies and protein bodies in cotyledon cells of the two varieties had begun to form while the pegs grew into the soil 10 days. With the number of lipid bodies and protein bodies increasing ceaselessly, the size of starch grains increased at first and then narrowed gradually with cotyledon development. The time when lipid bodies of ‘XB023’ reached maximum size was earlier than that of ‘Luhua 9’, and the time of rapid accumulation of lipid bodies in ‘Luhua 9’ was longer than that of ‘XB023’. The protein bodies of the two varieties both reached the maximum size when the pegs grew into the soil for 40 days. The number of protein bodies of ‘XB023’ grew fast during the late period. The protein content of seeds was determined by size and number of protein bodies, and the fat content was mainly determined by the number of lipid bodies in the cotyledon cells.

Aim Phosphorus (P) is one of the most important nutritional elements required by plants. The objective of our study was to evaluate the effects of P fertilizer on root morphology, physiological characteristics and yield of peanut (Arachis hypogaea).
Methods Pool experiments were conducted to elucidate the influence of phosphorus application on peanut. The root system under different phosphorus levels (P-level) was analyzed using a WinRHIZO system to quantify root volume and morphology. The following parameters were determined for all treatments: root activity, catalase (CAT) activity, concentration of soluble protein and malondialdehyde (MDA). Yield was recorded during the harvest period and analyzed using SPSS 13.0.
Important findings During the pod-filling stage, the length, volume, surface area and tip numbers of root increased with increasing P-level. When P₂O₅ was applied at 30-90 kg·hm^-2, the above parameters increased by 3.5%-20.7%, 9.3%-21.9%, 9.7%-20.3% and 12.6%-21.4%, respectively, compared to the control (no P treatment) group. P-levels could affect enzyme activities. In P treatment group, the activity of superoxide dismutase (SOD), peroxidase (POD) and CAT was increased by 12.7%-20.6%, 14.8%-36.8% and 17.0%-41.8%, respectively. Some other parameters could be influenced by P availability, including increased root activity, soluble protein content nodule number and fresh nodule weight. In contrast, MDA content was decreased by 8.4%-19.5% after the P treatment. In the harvesting stage, all parameters decreased with increasing P-level, except the MDA content. But for most parameters, there were no statistically significant differences among treatments. The number of pods per plant, shelling percentage, economic coefficient and biological yield were enhanced with increasing P-level.

Aims Our objective was to examine the possibility of using SmartRoot, free software based on ImageJ, for the measurement of fine root length, surface area, volume and diameter of Hevea brasiliensis.
Methods Photos were taken at heights of 15 and 40 cm from the fine root samples before the samples were subjected to comparison for accuracy of measurement of fine root length, surface area, volume and diameter of H. brasiliensis. The same images were analyzed manually and semi-automatically as well. Then the results obtained from SmartRoot were compared with those from WinRhizo, an expensive, popular, professional software for root analysis.
Important findings The average normal root mean square errors (NRMSE) between 15 and 40 cm height for fine root length, surface area, volume and diameter were 2.87%, 15.73%, 32.38% and 16.88%, respectively. In addition, the NRMSE between manual and semi-automatic analysis for the same morphological parameters were 3.06%, 21.00%, 40.96% and 11.64%, respectively. Furthermore the NRMSE between SmartRoot and WinRhizo on fine root length, surface area, volume and diameter were 5.31%, 9.37%, 9.61% and 5.77%, respectively, signifying a high consistency between the two software systems. The results indicated that it is feasible to employ the SmartRoot system for determination of fine-root morphological parameters of H. brasiliensis due to its satisfactory accuracy, reliability, easy operation and time-saving advantages. For better accuracy, photos are recommended to be taken at the height of 15 cm and analyzed with the semi-automatic method.